Photo electric tube



A i 15, P. H. MACNEIL 1,871,626

PHOTO ELECTRIC TUBE Filed June 6, 1950 I W I INVENTORV WITNESSES fim/Z/Vmwez Patented Aug. 16, 1 932 UNITE TATES PAUL l-I. MACNEIL, or nunrrneron, NEW YORK PHOTO ELECTRIC TUBE Application filed June 6,

This invention relates to photoelectric tubes.

It is among the objects of the present invention to provide a novel and improved photoelectric or equivalent vacuum tube light-responsive device with which is associated means for overcoming the time lag of the operation of such tube, and means for maintaining said tube at a high pitch of responsiveness.

In the operation of photoelectric tubes, a pair of elements is provided in an evacuated shell, one of which elements is responsive to light whereby upon the admission of light to the tube, current is passed between the electrodes. It will be seen that there is a time lag due to the fact that the light must overcome any inertia characteristic of the tube before the light sensitive element has reached passage of electrons between the elements. In such devices, it will also be noted that feeble light source will not bring the light responsive elementto an active point because the energy therefrom isconsumed in overcoming the inertia characteristic referred to. The present invention provides a continuous predetermined energization for the light responsive element, which energization is not suflicient to bring the light energized element to actuation point, but maintains it at the end of the inertia point, whereby feeble light source will instantly bring the light responsive element beyond the inertia point,

thus rendering the tube more responsive to light and avoiding a great portion of the time lag.

In connection with the present invention,

various forms of constant energization source may be used. The invention is therefore not limited to such structural features as herein presented. I

Numerous other objects of the present invention will be apparent from a consideration of the followin specification taken in conjunction with the accompanying drawing, in which Figure 1 is a sectional view of one embodiment of the present invention;

1930. Serial in. 459,492.

. -Fig.2 is a sectional view of another form of the present invention, and I Y Fig.3 is a view of a third embodiment of the invention.

Referring more particularly to. Fig. 1 of the drawing, a photoelectrictube of conventional form is illustrated. The form-of the tube herein shown comprises the conventional glass shell or envelope 10, the inner surface of which is coated with selenium sulphate .or equivalent light-responsive material, a portion ll of the envelope being of clear glass to permit the entrance of light rays. The envelopelO is mounted'upon a conventional four-prong base- 12, one of the prongs of which is electrically connected by a conductor 13 to the selenium coating, while one of the other prongs'is connected bya conductor 14; to the other element 15 of the tube. the necessary degree of activity to cause the For providing an energization source suflicient to overcome the inertia of the light sensitive coating, thus to provide the coating in a state of energization not sufficient to operate the tube but sufiicient to overcome the inertia of the tube whereby feeble light source will speedily completely overcome the inertia, thus to actuate the tube, a conventional-electric light in the form of a lamp 16 is provided externally of the envelope. Two of the prongs of the base 12 are arranged to deliver electric energy through the conductors 17 V to light the lamp 16, which may be suitably supported by a bracket from the base 12.

In connection with this form of the invention, it will be seen that by control of the light source or lamp 16, it may be adjusted to deliver to the tube light not quite sufficient for energization of'the tube but suflicient to hold the tube in such state of semi-activity 9 that a feeble lightsource will speedily actuate it. In connection with this form of the in vention it will be understood that the device is not in any way restricted to the type of light source here shown, its structural mounting or its mode of energization. These fea tures are herein shown merely by way of illustration and an equivalent structure may obviously be used without departing from the spirit of the invent-ion.

By referring more particularly to Fig. 2, it will be seen that the form of the invention herein illustrated, provides a heat or light source filament 19. Within the shell 10, the general structural arrangement is, as indicated in Fig. 1, the filament being adapted for energization through the conductors associated with the two extra pnongsiof the base 12. In this form of the invention it .Will be seen that the filament 19 may through its heat or its light, actuate the selenium coating to overcome the inertia in the manner of the light source 16. This structure may have some advantage over theexterna l ligaht'soumoe in that the structural arrangement is more simple and the positioning-of the supplementary energiz-aftion source is directly within the tube, thus overcoming oentaln possible variations or fluctuations in the'tu-he notion.

I By referring more particularly to 3, "it he seen that i f desi red, the fi la'mont 959, as i l'lus'tra'ted in Fig. 2, may Ebe positioned within-the shell 1'0, bm't shielded therefrom ihy separate individual-envelope or shllQO. By this arrangement, 'arn y diseh-arge of electrons from the filament 19 or the danger of any electronic adtion between the filament l9 and the selenium coating is preventedaccordance tv ith 'the present invention,

Y 7 it will be mnders'tood'fiha't the invention is not confined to any speoi fic arrangemei-its'here provided and that numerous ohanges, modifieations and the tall use of-equivahnts may be resorted to without departing from the spiritor scope of the invention as outlined "in the appended claims.

A photoelectric including an en- We lo pe and supporting base therefor, an anode, a selenium sulphate mem her acting as a photo-cathode, an energizing T'fila-ment supported said base for-'energ izat ion to mamtihe photo-cathode ofi'said tube just below its actuation point, said filament being positioned Within said envelope to be energized through said base, and an individual (envelope withinsa id first-mentioned envelope sealingsaid-filament with respect to --said'firs'tmentioned envelope.

2. A photoelectric tube inludimrg an -envelope, a supporting base for the envelope,

anode positioned in said envelope, a selenium sulphate coating in-terior'ly or said envelope and acting as a photo -cafihodemnd-an energizing member formed as a source of 9 "light positioned to energize said photocathode to a point just below its adtuation point. PAUL H. MACNEilL. 

